Hi, I'm designig a Sprinkler system that fits a low pressure water system. My water pipe before my meter is 1 inch after the meter it's 1/2 inch. Now I want to design my system with a 1 inch main line and 1 1/4 inch lateral lines(Cheaper, and Complies with City Municipal Code). According to irrigation websites 1 1/4 inch poly pipe should give me 32 GPM and I plan on installing 12 sprinkler heads most of them running at 1.89 GPM. Can this be done and will it run effectively extra GPM is no problem to me this is just an estimate.